Talk:Copper(II) oxide

It's Not Easy Being Green
It is my understanding that copper (II) oxide is green, what with pennies and copper alloys forming a green patina over time. Where was the picture in the description found and why is it black? Note that some Wikipedia pages call copper (II) oxide a green powder. Kyoobur9000 (talk) 16:51, 8 December 2012 (UTC)

Just to clarify in case others have this same question, Cu(II) oxide is black. The green material is not an oxide, but rather a mix of copper (II) hydroxide and copper (II) carbonate. Copper (II) oxide will readily form hydroxides in the presence of water, and these hydroxides will react with acid gases (i.e. carbon dioxide) to form copper (II) carbonate hydroxides. Other acid gases can also be involved (e.g. SO3) if they are present. This is the stuff that forms the green patina on aged copper, brass and bronze.

c.f. wikipedia's own page on basic copper carbonate

64.106.125.231 (talk) 06:59, 23 October 2019 (UTC)

Wilson's disease
The "health effects" section mentions that prolonged exposure to the substance can cause Wilson's disease. When I checked the source, the MSDS described increased copper toxicity in people with Wilson's disease, but did not claim that exposure to copper could cause the disease.

A check of the Wilson's disease page indicates that the disease is only hereditary in nature, so I am removing the claim. --Pyrochem 00:57, 29 August 2007 (UTC)

Use in disposal
These equations were under the 'Use in disposal' section with no explanation. If someone can write an explanation, please do so and move these back into the article.--Bfesser (talk) 00:10, 5 February 2008 (UTC)
 * C6H5OH + 14CuO → 6CO2 + 3H2O + 14Cu
 * C6Cl5OH + 2H2O + 9CuO → 6CO2 + 5HCl + 9Cu

These reactions are the decomposition of phenol and pentachlorophenol, respectively, with copper oxide. --98.221.179.18 (talk) 20:54, 19 February 2010 (UTC)

Melting point?
Is the melting point correct? I thougth it was 1026 dergrees celsius. —Preceding unsigned comment added by 130.238.56.104 (talk) 13:35, 19 May 2009 (UTC)

Personally not sure. Although I have seen a source that claims the point to actually be higher at 1446°C! DeadFire999 (talk) 13:28, 14 May 2015 (UTC)

Copper II oxide - Copper II hydroxide equilibrium
I have a question about the equilibrium condition that exists between copper II hydroxide and copper II oxide. Here is the reaction: Cu(OH)2 + heat ←→ CuO + H2O When heat is added, it drives the equilibrium to the right, forming more copper II oxide. When it is exposed to excessive moisture, it absorbs water to form copper II hydroxide again. But why does copper II hydroxide turn into copper II oxide when it is moist? I think that that would contradict Le Chatalier's principle. Just a question. --Cheminterest (talk) 20:22, 16 March 2010 (UTC)

You can think about it like this. When heated Cu(OH) dries out to CuO, although due to its reactivity to moisture continues back to Cu(OH) when left in the presence of moisture. Remember though the collision theory can effect outcomes of either reaction. (I know this question was old, but maybe it will help others in the future?!) DeadFire999 (talk) 13:23, 14 May 2015 (UTC)

Protective layer?
Is copper(ii) oxide protective to the copper from further damage? Qwertyxp2000 (talk) 05:59, 19 August 2014 (UTC)

Yes, Qwerty2000, the oxidized layer will act to protect the layers of copper under the oxide layer. You can see the process with the Statue of Liberty. DeadFire999 (talk) 18:49, 19 May 2015 (UTC)

"When cupric oxide is substituted for iron oxide in thermite the resulting mixture is a low explosive, not an incendiary."
What in the world is the basis for this claim? Copper(II)oxide thermite is called Cadweld. It has been used for decades with no more danger of explosion than iron bearing thermite mixtures. I have shot many charges of Cadweld and have some pictures that clearly are not explosions. Please reevaluate the source material on this "explosive". — Preceding unsigned comment added by 2602:301:7705:75E0:B91F:2C05:D00E:545 (talk) 10:15, 27 December 2015 (UTC)

Deleted battery claim
I deleted the sentence describing the use of CuO in Li batteries. 1) There was no reference provided. 2) CuO is not a typical cathode material for any Li-based battery. 3) The sentence seemed to imply Li metal was used as the anode, which is definitely wrong. — Preceding unsigned comment added by Chris Barile (talk • contribs) 04:57, 11 February 2016 (UTC)

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Not paramelaconite
Paramelaconite is a natural Cu(I) Cu(II) oxide - it is not equal to Cu(II) oxide. Only tenorite fits to CuO.Eudialytos (talk) 18:28, 21 October 2017 (UTC)
 * Removed. --Vsmith (talk) 18:48, 21 October 2017 (UTC)

Band Gap
Hello, currently the article states:

>The work function of bulk CuO is 5.3eV[4]

>Copper(II) oxide is a p-type semiconductor, with a narrow band gap of 1.2 eV.

These seemingly contradictory statements can be both true if the second sentence is referring to some kind of special form of CuO (e.g. a thin film?). Since the second sentence is unsourced, I suggest removing it unless a source backing up this claim is found, and the sentence amended to reflect the particular type of CuO in question.

64.106.125.231 (talk) 07:07, 23 October 2019 (UTC)